The Ali and Sonny Bill show is set to be carted into the next phase of the All Blacks' season.

Although the chances of the controversial Williams' boys playing together in the Rugby Championship appear remote, it seems inevitable the towering lock and powerful midfielder will be named in coach Steve Hansen's 28-man squad on Sunday.

Hansen yesterday confirmed midfielder Sonny Bill has been permitted by his Japanese club Panasonic to play the opening tests against the Wallabies on August 18 and 25 while Conrad Smith recovers from his eye injury.

Ali, a veteran of 75 tests who will not play the opening two tests - at least - because he is still recovering from knee surgery, will be flung another lifeline despite his mediocre form culminating in his disappointing performance against Ireland in Christchurch on June 16.

While Sonny Bill's decision to briefly prolong his All Blacks career has been welcomed by Hansen, the coach may yet be forced to call in an extra second rower until Ali is fit.

“We are hoping we will get, at least, a couple of games out of him," Hansen said in reference to the lock.

Despite the Crusaders' Luke Romano expected to be available for the Sydney test - the shoulder he injured during last weekend's Super semifinal is predicted to take two weeks to heal - Hansen could select another second rower as insurance in case Brodie Retallick, Sam Whitelock or Romano join Williams in the rugby casualty ward.

Hansen could contemplate adding the in-form Craig Clarke, who is no certainty to lead the Chiefs in Saturday night's Super final against the Sharks because of a knee injury.

Jason Eaton and Tom Donnelly are other options but by not adding them to the 28-man training group, Hansen has indicated they are down the order. Donnelly will also soon head to Japan.

Although Sonny Bill Williams' return will not be universally accepted by fans, especially those who would prefer Hansen select a player who has remained loyal to the New Zealand Rugby Union, his fine form with the Chiefs will prove too irresistible to ignore.

“There are a lot of things said about Sonny that aren't quite right," Hansen said.

“He's a very, very staunch New Zealander, he's very proud to wear the All Black jersey . . .

“We got the response we would expect from him because that's the way he has always been in our environment," he said.